The present invention relates to an image forming apparatus.
A conventional image forming apparatus of an electro-photography type such as a printer, a copier, a facsimile, a multi-function product, and the likes is provided with a photosensitive drum; a charging roller for charging the photosensitive drum with a specific polarity or potential; an exposure device for forming a static latent image on the photosensitive drum thus charged; a developing roller for developing the static latent image to form a toner image; a transfer roller for transferring the toner image to a sheet; and a fixing device for fixing the toner image to the sheet.
In the conventional image forming apparatus, a physical force is applied to toner as developer to form a uniform layer thereof on the developing roller. Further, after toner remains on the photosensitive drum without moving to the sheet upon transferring the toner image, the charging roller applies a physical force to toner. In such a case, frictional heat is generated, and toner may be crashed or agglomerated due to the frictional heat, thereby deteriorating toner.
When toner is deteriorated, toner thus deteriorated tends to accumulate in the developing device as a printing operation proceeds. Accordingly, there have been problems such as a variance in an image density, low reproducibility of dots constituting an image, and a blurred image. To this end, it is configured such that toner thus deteriorated inside the developing device is discharged to the photosensitive drum, so that a cleaning blade abutting against the photosensitive drum scrapes off toner, thereby collecting toner in a waste toner box (refer to Patent Reference).    Patent Reference: Japanese Patent Publication No. 2004-045481
In the conventional integrated image forming unit described above, when a plurality of sheets is printed continuously in a continuous printing operation and toner is discharged, it is difficult to sufficiently scrape off toner thus discharged with the cleaning blade, thereby causing a problem in cleaning.
In view of the problems described above, an object of the present invention is to provide an image reading apparatus capable of solving the problems of the conventional image forming apparatus. In the image forming apparatus of the present invention, even when a plurality of sheets is printed continuously in a continuous printing operation, it is possible to sufficiently scrape off toner discharged. Accordingly, it is possible to prevent a problem in cleaning.
Further objects and advantages of the invention will be apparent from the following description of the invention.